摘要:
A waveguide parametric device including a multi-mode waveguide having orientation layers formed in a propagation direction of a signal beam and a pump beam propagating down the waveguide. The orientation layers are oppositely oriented to provide non-linear coupling between the pump beam and the signal beam and have a periodicity that provides quasi-phase matching for a fundamental propagation mode, where the waveguide has a size to accommodate multi-mode wave propagation.
摘要:
An apparatus and method for high power amplification in a multimode fiber amplifier. The apparatus includes a diffraction limited low power laser, a multimode fiber amplifier, and a lens. The multimode fiber amplifier is coupled to the low power laser to amplify the low power laser output. The multimode fiber amplifier has a length that is set to a phase-matching length at which the transverse modes of the multimode fiber amplifier are in phase. The lens is coupled to the multimode fiber amplifier and outputs a kilowatt (KW)-level, diffraction-limited output beam from the multimode fiber amplifier.
摘要:
A direct diode laser system includes N laser head assemblies (LHAs) generating N output beams, N optical fibers receiving respective N output beams and generating N received output beams, and a torch head recollimating and focusing the N received output beams onto a single spot. Preferably, each of the laser head assemblies of the direct diode laser system includes M modules generating M laser beams, wherein each of the M laser beams has a corresponding single wavelength of light. M-1 dichroic filters, wherein each of the M-1 dichroic filter transmits a corresponding one of the M laser beams and reflects all other wavelengths, and a fiber coupling device collecting the M laser beams to produce a respective one of the N output beams. In an exemplary case, the M-1 dichroic filters function as band pass filters. A method of generating a high fluence, high power laser beam is also described.
摘要:
A fiber optic phased array and control method are provided for controllably adjusting the phase and amplitude of the optical signals emitted by a plurality of fiber optic amplifiers to compensate for atmospheric turbulence. The fiber optic phased array also includes a sensor assembly for detecting: (i) the phase of the optical signals that are emitted by the fiber optic amplifiers, and (ii) both the phase and the amplitude of the optical signals that have been reflected by the target. The fiber optic phased array also includes phase modulators and a gain adjustment mechanism for altering the phase and the amplitude of the optical signals propagating along the fiber optic amplifiers to compensate for modifications in the phase and amplitude that will be introduced by atmospheric turbulence. Among other things, the amplitude control of the optical signals is not adversely effected by intensity nulls in the reflected wavefront.
摘要:
Methods and apparatus are provided for modifying a free electron laser (FEL) to produce a non-diverging laser beam. A relativistic electron beam is converted to a Bessel beam in an FEL resonator with conical end mirrors, and the Bessel beam is coupled to the optical field within the laser resonator. The resultant laser beam is propagated with minimal divergence, and is wave corrected at the resonator output to produce a uniform intensity circular beam. The laser beam can be of smaller diameter than that of a conventional resonator due to its diffractionless propagation, which enables the magnetic structure gap within the resonator to be smaller, thus producing a higher optical gain.
摘要:
A laser diode array is formed on a substrate (310) in which a number of parallel grooves (312) are formed. A metal layer (410) is formed on the grooves (312). Laser diode bars (314) are fitted in alternate grooves, and every other groove is left vacant to serve as a cooling channel (316). The array is immersion cooled in a housing (210). Liquid coolant is circulated through the housing (210) and through a heat exchanger (216). The liquid coolant flows over a major surface of the substrate (310) and through the cooling channels (316). Thus, heat is removed by circulating fluid from three sides of the laser diode bars (314). Such high-performance cooling permits the laser diode array to have a greater power density.
摘要:
A micro-doppler ladar comprising a tunable laser to identify an unknown constituent of a gaseous cloud or region at a safe distance from the cloud or region. The tunable laser produces a laser beam tunable over a range of different frequencies. Each frequency produces a different vibrational response in the constituent in the gaseous cloud when the cloud or region is illuminated by the laser beam. A micro-doppler ladar system then interprets a back scattered beam to determine the induced vibrations. The determined induced vibrations can then be compared to known vibrations stored in a look-up table to identify the specific constituent(s) in the cloud or region.
摘要:
An optical fiber amplifier has an anisotropic numerical aperture to optimally couple pump energy into the pump core of a dual-clad fiber. The optical fiber consists of a dual-clad fiber having a longitudinally extending inner core, an outer core surrounding the inner core, and a cladding layer at least partially surrounding the outer core. The outer core is capable of transmitting pump energy to thereby amplify signals propagating through the inner core. Further, the outer core is capable of accepting pump energy within a first range of acceptance angles in a first direction and within a second range of acceptance angles in a second direction that is perpendicular to the first direction. The outer core and the cladding layer are structured such that a numerical aperture of the fiber amplifier in the first direction is different than the numerical aperture of the fiber amplifier in the second direction.
摘要:
There are provided an apparatus and method for friction welding structural members. The apparatus includes a connected shank and probe. The probe defines an absorption surface and a cavity extending thereto. The absorption surface is configured to receive electromagnetic radiation from an electromagnetic radiation source such as a light source or RF generator. The radiation heats the probe, supplementing the heat generated by friction between the probe and the structural members, and thereby increasing the speed at which the probe can be used to frictionally weld the structural materials.
摘要:
A fuel cell device for generation of electricity from a polar oxidizer liquid and a non-polar fuel fluid includes a cathode in contact with the polar oxidizer liquid; an anode in contact with the non-polar fuel fluid; and a separator for separating the polar oxidizer liquid from the non-polar fuel fluid. The separator is made from material that is lyophobic with respect to the oxidizer liquid, and has a plurality of apertures, which are appropriately sized and spaced to form a meniscus in each aperture. The meniscus forms a liquid heterointerface between the conductive polar oxidizer liquid and the non-polar fuel fluid providing a controlled contact surface for oxidation processes. The fuel side of the separator may be coated with a conductive material to form the anode, in electric contact with the perimeter of the meniscus, and the cathode may be formed on the oxidizer side of the separator.